Patient socket performance is a critical barrier to progress in rehabilitation, the most common source of patient dissatisfaction and part of a growing medical and socioeconomic problem. Poor socket performance is a greatly uncharacterized multi-factorial problem that leads to skin degeneration and patient discomfort (~75% of all patients). This proposal has a two-folded scope: (a) to combine two novel socket technologies (elevated vacuum-EV and variable volume VV system) in order to enable for the first time real-time controllability of socket elevated vacuum and socket internal volume, and (b) to evaluate its innovative socket prototype in a number of in- and out-of-lab clinical trials by introducing a universal Socket Performance Index (SPI) parameter (that is experimentally verified) for reliable, non-patient specific socket device assessment. Thorough validation of the socket prototype system for very strenuous activities, robust feasibility studies will expand along its entire structural and functional properties, including sensitivity, operability, safety and durability, and will be completed by functional tests in clinical trials in-and-out of the laboratory. The work proposed here will bring to the market horizon a novel device (iSOCKET) and new methodologies that stem from years of collaboration of a cohort of companies and Academia. iSOCKET will enhance the autonomy of patients (improve on the time of continuous pain-free socket use, improve SPI as compared to competitive products) and will solve the long awaited challenges in socket performance associated with very strenuous activities. The iSOCKET device will evolve into an affordable, practical socket with real-time pressure/shear/stress relief capabilities. iSOCKET hopes to prove the new choice for preventative interventions whereas the proposed work will also deliver new clinical tools to support daily fitting, rehabilitation, and monitoring of lower limb prosthesis users. The proposal depends in the synergy of a very diverse consortium of companies, hospitals, user groups, clinicians and academic Centers. SSDL will take advantage of technological maturity and cost/efficiency ratios in the proposed technology to overcome critical barriers in scientific knowledge and clinical practice. PUBLIC HEALTH RELEVANCE: The iSOCKET prosthetic device combines two novel socket technologies in order to enable real-time controllability of socket elevated vacuum and socket internal volume and is designed to be an affordable, practical socket with real-time pressure/shear/stress relief capabilities. The product is intended to support researchers and clinicians in their optimization of patient care by improving patient autonomy and mobility. Research supporting improved fitting and rehabilitation of prosthesis users will result in greater patient mobility, leading to multiple long-term health benefits.